Flooding at Cold Start, Edelbrock 1407 on a 383

[gruveb]

I'm hoping someone can point me in the right direction. Here's the problem and the pertinent background:

383, 10:1 compression, dynoed 420 HP and 450 tq, it's this motor here: new motor.

I have a new Edelbrock 1407 that I put an electric choke kit on.

When it's cold outside and the motor is cold the motor floods badly upon start up. To start, I hit the gas once to engage the choke and then start it. It'll stumble for a few seconds and stall. Crank it again and it stalls again. Suddenly, it's flooded. If i'm lucky enough to get it to run, the choke is functioning properly. The mixture screws are set correctly (when warm) and the timing is 14*.

When I had the smaller 600 carb on, none of this happened.

I've checked the float height, it's fine. I put on a fuel pressure regulator, it's 5.5 psi now.

Any ideas?

[68gmsee]

If there's no leakage into the intake when sitting and it starts up and runs okay when engine is warmed up, then everything points to the choke adjusted to tight.

With engine completely cold, adjust the choke so that it just starts to open, and then slowly adjust it so that it just closes. If that doesn't do it for you and it still flood badly, then the choke is defective. Can't think of anything else at this time.

[cadillac_al]

After cold start up my Edlebrock choke will not open until I blip the throttle once. It does not have a normal choke pull off like a Qjet. I gather it is supposed to have some kind of internal vacuum operated choke pull off but I haven' t figured it out yet. When I start it, I let it blubber for about 2 seconds, blip the throttle to let the choke open 1/4" and it will sit and idle like it is supposed to. This is the only time I miss my Qjet but I have put up with it for 4 years now. Just a minor annoyance. If you aren't blipping your throttle after start up, then I don't see how your choke is supposed to open. Watch it next time you start it.

[Jimal]

Originally Posted by cadillac_al

After cold start up my Edlebrock choke will not open until I blip the throttle once. It does not have a normal choke pull off like a Qjet. I gather it is supposed to have some kind of internal vacuum operated choke pull off but I haven' t figured it out yet. When I start it, I let it blubber for about 2 seconds, blip the throttle to let the choke open 1/4" and it will sit and idle like it is supposed to. This is the only time I miss my Qjet but I have put up with it for 4 years now. Just a minor annoyance. If you aren't blipping your throttle after start up, then I don't see how your choke is supposed to open. Watch it next time you start it.

Are you sure you're electric choke is good and has power going to it with the engine on? The engine won't come off high idle until you blip the throttle, but if the choke is adjusted properly it should start opening soon after the key is turned on.

[geezer#99]

Originally Posted by gruveb

I'm hoping someone can point me in the right direction. Here's the problem and the pertinent background:

383, 10:1 compression, dynoed 420 HP and 450 tq, it's this motor here: new motor.

I have a new Edelbrock 1407 that I put an electric choke kit on.

When it's cold outside and the motor is cold the motor floods badly upon start up. To start, I hit the gas once to engage the choke and then start it. It'll stumble for a few seconds and stall. Crank it again and it stalls again. Suddenly, it's flooded. If i'm lucky enough to get it to run, the choke is functioning properly. The mixture screws are set correctly (when warm) and the timing is 14*.

When I had the smaller 600 carb on, none of this happened.

I've checked the float height, it's fine. I put on a fuel pressure regulator, it's 5.5 psi now.

Any ideas?

1. Lower your float level.
2. Lower your pressure to 4psi.
3. Increase your high idle speed to 1200 rpm.
4. Maximize your timing curve. As much initial as possible.

[GASoline71]

I agree ^^^

Plus that thing will like a lot more initial timing.

Gary

[crazy longhorn]

Lots of good advice....no argue, but I would like to add to the mix? Let us talk about timing....12- 14 initial, usually gets you into the spot? However, I like to focus more on the TOTAL @ 2800-3000 rpms, then set the vac timing(manifold source) @ idle, to 10-12 @ the crank. Understand that the vac timing drops out , under full throttle @ is used as a low rpm /part throttle crutch. Focus on the TOTAL timing, & all in spot.....I don't like to be past 34-35 degrees on a pump fuel street mill....on the track, with good fuel....around 38 degrees (no vac advance)? Longhorn

[gruveb]

Just a follow up to what I figured out because I ran across half a dozen issues like mine on various message boards and no one ever posted their solution!

First, I had the choke closed too much. When I installed the electric choke I was off by 120 degrees. That didn't cure my problem though, but it contributed.

Second, I installed a fuel pressure regulator. My mechanical pump was putting out crazy pressure.

Third, I verified that the floats were adjusted correctly.

Fourth, and this is what did it: I put in two steps leaner primary jets and the matching metering rod according to the manual from edelbrock. I swapped the springs to match the vacuum created by my engine. I went one step richer on the secondary jets. Now it still does a little coughing when cold, but I can drive it without issue.

[geezer#99]

And what did you set the timing at?

[gruveb]

The timing is still at 14* initial. I didn't believe that was the issue because it ran great with the other carb.

[geezer#99]

Is it a verified 14 degrees?
Have you proved your timing tab/balancer are spot on?
http://www.crankshaftcoalition.com/w...op_dead_center

Have you tried more initial?

[gruveb]

No, never verified it. It's running good now though.

[crazy longhorn]

Good to hear that she is working for you I should start another post on this, or you all can post replies........ IMHO, intial timing is a starting point, I tend to focus more on the TOTAL timing! I like to see around 34 degrees total on a street/mild mill. IMO, where the initial "falls", is not as important, as where the total is @ 3000 rpms? Set the vac advance around 10 degrees @ the crank, & you are pretty close. Longhorn

[gruveb]

Like Jaws 2 ... just when you thought it was safe to go back in the water...

This morning the truck wouldn't start. The weather's been stable, that's not the issue. I pull the air cleaner and see the choke wide open. I check and it's not bound up with anything. The alignment marks are the same, too.

I readjust the choke so it's barely open and try to start the truck. It's too late, the truck is already flooded. Plugs are fouled.

Then, I realized one of the problems...the ignition switch is so worn out on the truck that sometimes the switch is left on when the key looks off. There was power to the choke all night. I didn't check it, but I'm pretty certain it was warm.

[storm9c1]

If the choke was wide open (and normally it works fine), I'd say it is very plausible that your key was on all night.

On all of my old vehicles that do not already have an oil pressure light, I wire one up. So if I leave the key on without the vehicle running, I have a big red light in my face that comes with the added bonus of verifying oil pressure. Might be something to consider.